Fuel rail cups are used to mount respective inlets of fuel injectors to a fuel rail. The inlet of the fuel injector typically includes an O-ring mounted about the inlet. The fuel injector inlet is inserted into the fuel rail cup with an axial insertion force that is believed to be greater than about 45 pound-force. Problems may arise when a fuel injector inlet is inserted with the insertion force of such magnitude. If the injectors are inserted manually, the magnitude of the force may be too high for repeated manual operation. If the injectors are inserted by a machine, it is possible that the O-ring may be damaged during insertion because the magnitude of the force is such that the O-ring may be torn or degraded. Moreover, if the insertion force is high, there is more wear and tear on the insertion machine or the machine may simply stop inserting the specific injector.
It would be beneficial to reduce the insertion force required to insert a fuel injector inlet into the fuel rail cup such that there is less likelihood of damage to the O-ring, fuel rail cup inner surfaces or wear and tear on the insertion machine.